Vehicle seat

ABSTRACT

A head rest rear portion is supported to a seat back. A head rest front portion is movable forward and backward between a full-close position that is brought into contact with or close to the head rest rear portion and a full-open position that is a predetermined distance away from the head rest rear portion. A drive mechanism moves the head rest front portion. A detection sensor provided in the head rest front portion includes an electrode having a head portion detecting antenna electrode for detecting a head portion of an occupant at a time when the head rest front portion moves in the full-open position direction, and a finger detecting antenna electrode for detecting a finger of the occupant in a rear seat or the like at a time when the head rest front portion moves in the full-close position direction.

TECHNICAL FIELD

The present invention relates to a vehicle seat provided in a vehiclesuch as a motor vehicle or the like.

BACKGROUND ART

There has been known a vehicle seat which forecasts a collision from arear side of a vehicle and moves a head rest of the seat to a forwardside by a drive mechanism so as to protect an occupant. In this kind ofvehicle seat, for example, as described in Japanese National Publicationof Translated Version No. 2004-500273, in the case where the collisionis not generated after moving forward, the head rest is moved backwardby the drive mechanism, and is returned to a normal position.

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, if the occupant in its own seat or another seat grips the headrest after moving the head rest forward, there is a case that thegripping is an obstacle to a smooth backward motion of the head rest bythe drive mechanism.

Means for Solving the Problem

In accordance with the present invention, there is provided a vehicleseat comprising:

a head rest rear portion supported to a seat back;

a head rest front portion movable forward and backward between afull-close position which is brought into contact with or close to thehead rest rear portion and a full-open position which is a predetermineddistance away from the head rest rear portion;

a drive means for moving the head rest front portion; and

a detection sensor provided in the head rest front portion for detectinga head portion of an occupant at a time of moving in a full-openposition direction,

wherein the detection sensor is capable of detecting a finger of theoccupant in a forward side in a moving direction at a time when the headrest front portion moves in a full-close position direction.

In accordance with the vehicle seat, it is possible to well detect thehead portion of the occupant on the basis of a detection signal from thedetection sensor at a time when the head rest front portion moves in thefull-open position direction. On the other hand, in the case where theoccupant in a rear seat or the like puts a finger between the head restfront portion and the head rest rear portion, it is possible to detectthe finger of the occupant on the basis of the detection signal from thedetection sensor at a time of moving of the head rest front portion inthe full-close position direction.

Accordingly, in the case of detecting the finger between the head restfront portion and the head rest rear portion, it is possible to stop themovement of the head rest front portion in the full-close positiondirection or move the head rest front portion in an opposite direction.

The detection sensor may be provided with a head portion detectingantenna electrode for detecting the head portion of the occupant and afinger detecting antenna electrode for detecting the finger of theoccupant.

The head portion detecting antenna electrode and the finger detectingantenna electrode may be provided on the same film.

The detection sensor may be constituted by an electrostatic capacitancetype sensor, and the head portion detecting antenna electrode and thefinger detecting antenna electrode may be separated from each other soas to independently detect an electrostatic capacitance.

There may be provided with a switch circuit selecting the detectionsignal of any one of the head portion detecting antenna electrode andthe finger detecting antenna electrode.

The finger detecting antenna electrode may be invalidated at a time whenthe head rest front portion moves in the full-open position direction,and the head portion detecting antenna electrode may be invalidated at atime when the head rest front portion moves in the full-close positiondirection.

A threshold value of the detection signal from the detection sensor at atime when the head rest front portion moves in the full-open positiondirection may be different from a threshold value of the detectionsignal from the detection sensor at a time when the head rest frontportion moves in the full-close position direction.

The drive means may stop the movement of the head rest front portion inthe full-close position direction or may move the head rest frontportion in an opposite direction in the case where the finger isdetected between the head rest front portion and the head rest rearportion.

Effect of the Invention

In accordance with the vehicle seat on the basis of the presentinvention, in the case where the occupant in the rear seat or the likeput own finger between the head rest front portion and the head restrear portion, it is possible to detect the finger of the occupant so asto stop the movement of the head rest front portion in the full-closeposition direction or move the head rest front portion in the oppositedirection, on the basis of the detection signal from the detectionsensor at a time when the head rest front portion moves in thefull-close position direction, whereby it is possible to achieve asmooth forward and backward motion of the head rest.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view explaining a vehicle seat inaccordance with the present invention;

FIGS. 2( a) and 2(b) are side elevational views explaining an actuationof a head rest front portion;

FIG. 3 is a perspective view of a cushion member to which a detectionsensor is attached;

FIG. 4 is a plan view showing the detection sensor;

FIG. 5 is a back elevational view of the cushion member to which thedetection sensor is attached;

FIG. 6 is a block diagram showing an electric structure of a head restdevice for a vehicle;

FIG. 7 is a plan view showing another detection sensor; and

FIG. 8 is a block diagram showing an electric structure of the head restdevice for the vehicle.

DESCRIPTION OF REFERENCE NUMERALS

1 vehicle seat

3 seat back

11 head rest rear portion

12 head rest front portion

14 detection sensor

15 drive mechanism (drive means)

21 a, 41 head portion detecting antenna electrode

21 b, 42 finger detecting antenna electrode

22, 44 film

45 switch circuit

BEST MODE FOR CARRYING OUT THE INVENTION

A description will be in detail given below of an embodiment of avehicle seat in accordance with the present invention with reference tothe drawings.

FIG. 1 shows a side elevational view of a vehicle seat in accordancewith the present invention. The vehicle seat 1 is arranged in a driverseat side of a vehicle, and is provided with a sitting seat 2, a seatback 3 supported to the sitting seat 2 so as to move obliquely, and ahead rest device 10 for the vehicle. In this case, the present inventionmay be applied to a seat arranged in an assistant driver seat, or a seatarranged in a rear seat side.

The head rest device 10 for the vehicle is provided with a head restrear portion 11, a head rest front portion 12, a motor 13 serving as adrive means for moving the head rest front portion 12 with respect tothe head rest rear portion 11, a detection sensor 14 provided in thehead rest front portion 12, and an ECU 20 serving as a control means forcontrolling the drive of the motor 13 on the basis of a detection resultof the detection sensor 14 or the like.

The head rest rear portion 11 is supported to a head rest stay 5provided in an upper end portion of the seat back 3.

The head rest front portion 12 is structured such as to be movableforward and backward between a full-close position 12A which is broughtinto contact with or comes close to the head rest rear portion 11 asshown by a solid line in FIG. 1 and a full-open position 12B which is apredetermined distance away from the head rest rear portion 11 as shownby a two-dot chain line in FIG. 1. At a time of a normal operation ofthe vehicle, the head rest front portion 12 is arranged in thefull-close position 12A.

A drive mechanism 15 serving as the drive means is provided between thehead rest rear portion 11 and the head rest front portion 12, and thedrive mechanism 15 is driven by the motor 13 to be expanded andcontracted, whereby the head rest front portion 12 moves forward andbackward along a vehicle forward and backward (traveling) direction withrespect to the head rest rear portion 11.

The detection sensor 14 is provided in the head rest front portion 12,and corresponds to an electrostatic capacitance type sensor having aknown structure in which an electrostatic capacitance is changed inaccordance with a fluctuation of a distance L shown in FIG. 2( a) withrespect to a subject to be detected, that is, a head portion of anoccupant. In the detection sensor 14, basically, a detectedelectrostatic capacitance value becomes large as the head portion of theoccupant comes close to the detection sensor 14.

If a collision from a rear side of the vehicle is forecasted, the ECU 20controls the motor 13 so as to move the head rest front portion 12 fromthe full-close position 12A to the direction of the full-open position12B, and after that, return it to the original full-close position 12A,for example, in the case where the collision from the rear side of thevehicle is avoided after.

Further, when moving the head rest front portion 12 in the full-openposition direction 12B, the ECU 20 determines an approach between thehead rest front portion 12 and the head portion of the occupant on thebasis of the detection result of the detection sensor 14, in detail,detects that the detection sensor 14, that is, the head rest frontportion 12 comes close to the head portion of the occupant on the basisof an absolute capacitance change with respect to a referenceelectrostatic capacitance value of the detection sensor 14.

In more detail, when moving the head rest front portion 12 in thefull-open position direction 12B, the ECU 20 sets the electrostaticcapacitance value of the detection sensor 14 at a time point of startingthe movement of the head rest front portion 12 in the full-open positiondirection 12B as the reference electrostatic capacitance value, anddetermines that the head rest front portion 12 comes close to the headportion of the occupant at a time when an increasing amount of theelectrostatic capacitance value of the detection sensor 14 with respectto the reference electrostatic capacitance value becomes equal to ormore than a predetermined threshold value.

Then, the ECU 20 moves the head rest front portion 12 in the full-openposition direction 12B, and, if the ECU 20 determines that the head restfront portion 12 comes close to the head portion of the occupant, theECU 20 stops the movement of the head rest front portion 12 at a stopposition 12H of coming close to the head portion as shown in FIG. 2( b).On the other hand, the ECU 20 moves the head rest front portion 12 inthe full-open position direction 12B, and, in the case where theapproach between the head rest front portion 12 and the head portion ofthe occupant is not detected, the ECU 20 moves the head rest frontportion 12 to the full-open position 12B shown in FIG. 1 and stops it.

Next, a description will be given in detail of the detection sensor 14provided in the head rest front portion 12. FIG. 3 is a perspective viewof a cushion member to which the detection sensor is attached, FIG. 4 isa plan view showing the detection sensor, and FIG. 5 is a backelevational view of the cushion member to which the detection sensor isattached.

As shown in FIG. 3, the detection sensor 14 is formed as a film shape,and is attached to a cushion member 16 within the head rest frontportion 12. The detection sensor 14 is provided with an electrode 21,for example, formed by a conductor such as a silver paint, a carbonprint, a copper foil or the like, and the electrode 21 is sandwichedbetween two films 22 made of a thin resin having a flexibility, as shownin FIG. 4. In this case, a film hole 14 a is formed in a center portionof the detection sensor 14.

The electrode 21 is provided with a head portion detecting antennaelectrode 21 a formed as an annular shape having a hole portion 21 ewith a larger diameter than the film hole 14 a and having asubstantially constant width in a circumferential direction, and aplurality of finger detecting antenna electrodes 21 b arranged in upperand lower sides and both side portions of the head portion detectingantenna electrode 21 a, in a center portion of the electrode 21, and thefinger detecting antenna electrodes 21 b are coupled to the head portiondetecting antenna 21 a via coupling portions 21 c.

The above detection sensor 14 is structured such that the head portiondetecting antenna electrode 21 a of the electrode 21 is attached to afront surface of the cushion member 16 constructing the head rest frontportion 21. Further, each of the coupling portions 21 c of the electrode21 is bent to a side portion of the cushion member 16, and anapproximately half in a width direction of the finger detecting antennaelectrode 21 b is bent to a back surface side of the cushion member 16,as shown in FIG. 5.

Further, the detection sensor 14 has a connection terminal portion 21 dextending to a lower side from a lower portion in the center of theelectrode 21, and the connection terminal portion 21 d is introducedinto a wiring hole 16 a formed near a lower side in the front surfaceside of the cushion member 16, and is connected to a signal line fromthe ECU 20 which is wired along the head rest stay 5.

Next, a description will be given of an electric structure of the headrest device 10 for the vehicle provided in the vehicle seat 1 mentionedabove.

As shown in FIG. 6, the head rest device 10 for the vehicle isstructured such as to be provided with the ECU 20, the motor 13connected to the ECU 20, the detection sensor 14, a power supply unit26, a collision determining portion 27 and the like.

Further, the ECU 20 is structured such as to be provided with a CPU 31,a power supply circuit 32, a vehicle information input circuit 33, amotor drive circuit 34, a detection sensor circuit 35 and a memory 36which are connected to the CPU 31. The CPU 31 is connected to theelectric power unit 26 via an ignition switch (IGSW) 37, and isstructured such that an electric power is fed from the electric powerunit 26 via the power supply circuit 32 on the basis of an ON operationof the ignition switch 37.

Further, the CPU 31 inputs a vehicle information such as a backwardapproach information or the like from the collision determining portion27 via the vehicle information input circuit 33. The collisiondetermining portion 27 is connected to a radar (not shown) installed ina bumper in a rear portion of the vehicle, inputs a signal from theradar to comprehensively determine a relative speed and a distance withrespect to the following vehicle and a speed of the vehicle, anddetermines whether or not the following vehicle comes into collisionwith its own vehicle, or whether or not there is a possibility that thefollowing vehicle comes into contact with its own vehicle.

The determination result is output to the vehicle information inputcircuit 33. Further, the CPU 31 is connected to the motor 13 via themotor drive circuit 34, and controls the motor drive circuit 34 to drivethe motor 13.

In the case where a collision from the backward side of the vehicle isforecasted, the CPU 31 starts forward moving so as to move the head restfront portion 12 in the full-open position 12B direction. Then, if theCPU 31 determines that an increasing amount of an electrostaticcapacitance value of the detection sensor 14 reaches a head portiondetection threshold value CH stored in the memory 36, the CPU 31 stopsthe head rest front portion 12. Thereafter, the CPU 31 starts backwardmoving so a to move the head rest front portion 12 in the full-closeposition 12A direction and store the head rest front portion, after anelapse of a predetermined time for which the head portion of theoccupant can be sufficiently protected.

In this case, if the finger exists between the head rest rear portion 11and the head rest front portion 12 because of, for example, gripping ofthe head rest rear portion 11 by the occupant in the rear seat, thefinger detecting antenna electrodes 21 b come close to the finger in thedetection sensor 14. Thereby, the electrostatic capacitance value of thedetection sensor 14 is increased.

Accordingly, if the CPU 31 determines that the increasing amount of theelectrostatic capacitance value of the detection sensor 14 reaches afinger detection threshold value CF stored in the memory 36 at a time ofbackward moving, the CPU 31 stops the head rest front portion 12. Inthis case, the finger detection threshold value CF is set to anelectrostatic capacitance value which is smaller than the head portiondetection threshold value CH.

Thereby, it is possible to smoothly move the head rest front portion 12forward in such a manner as to prevent the head rest front portion 12from being stopped by the detection of the finger, at a time of movingforward, and it is possible to well detect the small increase of theelectrostatic capacitance by the finger to stop the head rest frontportion 12, at a time of moving backward. In this case, the head restfront portion 12 may be moved in an opposite direction at a time ofdetecting the finger between the head rest front portion 12 and the headrest rear portion 11.

As mentioned above, in accordance with the vehicle seat on the basis ofthe embodiment mentioned above, it is possible to well detect the headportion of the occupant on the basis of the detection signal from thedetection sensor 14 at a time when the head rest front portion 12 movesin the full-open position 12B direction. On the other hand, in the casewhere the occupant in the rear seat or the like puts own finger betweenthe head rest front portion 12 and the head rest rear portion 11, it ispossible to detect the finger of the occupant on the basis of thedetection signal from the detection sensor 14 at a time when the headrest front portion 12 moves in the full-close position 12A direction.

Thereby, in the case of detecting the finger between the head rest frontportion 12 and the head rest rear portion 11, it is possible to stop themovement of the head rest front portion 12 in the full-close position12A direction, or move the head rest front portion 12 in the oppositedirection, thus, it is possible to achieve a smooth backward motion ofthe head rest front portion 12.

Further, since the head portion detecting antenna electrode 21 a of theelectrode 21 is integrally formed with the finger detecting antenna 21 bby the film 22, it is possible to achieve a low cost in comparison withthe case where a plurality of electrodes are individually provided.

Further, since the threshold value CH of the increasing amount of theelectrostatic capacitance value at a time of detecting the head portionis differentiated from the threshold value CF of the increasing amountof the electrostatic capacitance value at a time of detecting thefinger, it is possible to suppress an erroneous detection of the headportion and the finger having the different electrostatic capacitancesat a time of detecting and suitably carry out the detection.

Further, since a protrusion of a sensitivity in the center portion canbe suppressed as much as possible by forming the hole portion 21 e inthe center portion of the head portion detecting antenna electrode 21 a,it is possible to obtain a sensitivity characteristic that issubstantially flat from the center over an outer circumferential side.Thereby, the detection sensor 14 can detect the head portion withoutbeing affected by a position of the head portion of the occupant in aplane direction.

Next, a description will be given of another embodiment. In this case,the same reference numerals are attached to the same structure portionsas those of the embodiment mentioned above and a description thereofwill be omitted.

FIG. 7 is a plan view of an electrode constructing a detection sensor.As shown in FIG. 7, the detection sensor 40 is provided with a headportion detecting antenna electrode 41, a finger detecting antennaelectrode 42 and a grand electrode 43 which are, for example, formed bya conductor such as a silver print, a carbon print, a copper foil or thelike. Further, the head portion detecting antenna electrode 41, thefinger detecting antenna electrode 42 and the ground electrode 43 aresandwiched between two films 44 made of a thin resin having aflexibility. A film hole 40 a is formed in a center portion of thedetection sensor 40.

The head portion detecting antenna electrode 41 is formed as an annularshape having a hole portion 41 a with a larger diameter than the filmhole 40 a, in a center portion thereof, and a width thereof issubstantially constant in a circumferential direction. The groundelectrode 43 is formed as a band shape, and is arranged so as to bespaced along an outer circumference of the head portion detectingantenna electrode 41.

The finger detecting antenna electrode 42 has an annular connectionportion 42 a extending along an outer circumference of the groundelectrode 43, a plurality of finger detecting antenna electrodes 42 barranged in an upper portion and both side portions of the connectionportion 42 a, and coupling portions 42 c coupling the connection portion42 a and the finger detecting antenna electrodes 42 b.

The detection sensor 40 mentioned above is structured such that the headportion detecting antenna electrode 41, the ground electrode 43 and theconnection portion 42 a of the finger detecting antenna electrode 42 areattached to a front surface of the cushion member 16 constructing thehead rest front portion 12. Further, each of the coupling portions 42 cof the finger detecting antenna electrodes 42 is bent to a sidewarddirection, and an approximately half in a width direction of the fingerdetecting antenna electrode 42 b is bent to a back surface side of thecushion member 16.

Further, the detection sensor 40 has connection terminal portions 41 b,42 d and 43 a extending to a lower portion in the center from the headportion detecting antenna electrode 41, the finger detecting electrode42 and the ground electrode 43, and these connection terminal portions41 b, 42 d and 43 a are introduced into a wiring hole 16 a formed near alower side in a front surface side of the cushion member 16 and areconnected to a signal line from the ECU 20 wired along the head reststay 5.

Then, in the head rest device 10 for the vehicle provided with thedetection sensor 40, a switch circuit 45 is provided between thedetection sensor 40 and the detection sensor circuit 35, as shown inFIG. 8. The switch circuit 45 transmits a detection signal from any oneof the head portion detecting antenna electrode 41 and the fingerdetecting antenna electrode 42 to the detection sensor circuit 35, onthe basis of a command from the CPU 31.

Specifically, if the collision from the rear side of the vehicle isforecasted, the CPU 31 starts the forward movement so as to move thehead rest front portion 12 in the full-open position 12B direction. Atthis time, the switch circuit 45 transmits the detection signal from thehead portion detecting antenna electrode 41 to the detection sensorcircuit 35 on the basis of the command from the CPU 31. Then, if the CPU31 determines that the increasing amount of the electrostaticcapacitance value detected by the head portion detecting antenna 41 ofthe detection sensor 40 reaches the head portion detection thresholdvalue CH, the CPU 31 stops the head rest front portion 12.

Thereafter, the CPU 31 starts the backward movement so as to move thehead rest front portion 12 in the full-close position 12A direction andstore the head rest front portion 12, after an elapse of a predeterminedtime for which the head portion of the occupant can be sufficientlyprotected. At this time, the switch circuit 45 transmits the detectionsignal from the finger detecting antenna electrode 42 to the detectionsensor circuit 35 on the basis of the command from the CPU 31.

Thereby, if the CPU 31 determines that the increasing amount of theelectrostatic capacitance value detected by the finger detecting antenna42 of the detection sensor 40 reaches the finger detection thresholdvalue CF stored in the memory 36 at a time of moving backward, the CPU31 stops the head rest front portion 12.

As mentioned above, in accordance with the vehicle seat on the basis ofthe present embodiment, in the case where the occupant in the rear seator the like puts own finger between the head rest front portion 12 andthe head rest rear portion 11, since it is possible to detect the fingerof the occupant on the basis of the detection signal from the detectionsensor 40 at a time when the head rest front portion 12 moves in thefull-close position 12A direction so as to stop the movement in thefull-close position 12A direction of the head rest front portion 12 ormove the head rest front portion 12 in the opposite direction, it ispossible to achieve a smooth backward motion of the head rest frontportion 12.

Further, since the head portion detecting antenna electrode 41, thefinger detecting antenna electrode 42 and the ground electrode 43 areintegrally formed by the film 44, it is possible to achieve a costreduction in comparison with the structure individually provided with aplurality of electrodes.

Particularly, in this embodiment, since the head portion detectingantenna electrode 41 for detecting the head portion is separated fromthe finger detecting antenna electrode 42 for detecting the finger so asto be independent, it is possible to increase a detection precision ofeach of the head portion and the finger.

Further, since the detection signals from the head portion detectingantenna electrode 41 and the finger detecting antenna electrode 42 areswitched by the switch circuit 45, it is possible to simplify thecircuit structure and reduce the cost in comparison with the case thatthe detection sensor circuit 35 is provided in each of the head portiondetecting antenna electrode 41 and the finger detecting antennaelectrode 42.

Further, since the detection signal of one of the head portion detectingantenna electrode 41 and the finger detecting antenna electrode 42 isvalidated by the switch circuit 45, whereby the other electrode which isunnecessary for detecting the head portion or detecting the finger isinvalidated, it is possible to improve a precision of the detectionsignal from the validated electrode.

Further, since the hole portion 41 a is formed in the center portion ofthe head portion detecting antenna electrode 41, it is possible tosuppress a protrusion of the sensitivity in the center as much aspossible. Further, since an electric line of force around the headportion detecting antenna electrode 41 is oriented forward, that is, inthe occupant head portion direction by the ground electrode 43 arrangedaround the head portion detecting antenna electrode 41, it is possibleto obtain a sensitivity characteristic that is substantially flat fromthe center over the outer circumferential side.

Thereby, in this detection sensor 40, it is possible to detect the headportion without being affected by the position of the head portion ofthe occupant in the plane direction.

INDUSTRIAL APPLICABILITY

In accordance with the vehicle seat on the basis of the presentinvention, even in the case where the occupant in the rear seat or thelike puts own finger between the head rest front portion and the headrest rear portion, it is possible to detect the finger of the occupant,and it is possible to stop the movement of the head rest front portionin the full-close position direction and move the head rest frontportion in the opposite direction, therefore, it is possible to achievethe smooth backward motion of the head rest front portion. Accordingly,the present invention can be widely applied to the vehicle seat havingsuch a demand.

1. A vehicle seat comprising: a head rest rear portion supported on aseat back; a head rest front portion movable forward and backwardbetween a full-close position which is brought into contact with orclose to the head rest rear portion and a full-open position which is apredetermined distance away from the head rest rear portion; a drivemeans for moving the head rest front portion; and a detection sensorprovided in the head rest front portion for detecting a head portion ofan occupant at a time of moving in a full-open position direction,wherein the detection sensor detects any occupant's finger that isplaced between the head rest rear portion and the head rest frontportion at a time when the head rest front portion moves in a full-closeposition direction.
 2. The vehicle seat as claimed in claim 1, whereinthe detection sensor is provided with a head portion detecting antennaelectrode for detecting the head portion of the occupant and a fingerdetecting antenna electrode for detecting the finger of the occupant. 3.The vehicle seat as claimed in claim 2, wherein the head portiondetecting antenna electrode and the finger detecting antenna electrodeare provided on film, wherein the film is the same film.
 4. The vehicleseat as claimed in claim 2, wherein the detection sensor is constitutedby an electrostatic capacitance type sensor, and the head portiondetecting antenna electrode and the finger detecting antenna electrodeare separated from each other so as to independently detect anelectrostatic capacitance.
 5. The vehicle seat as claimed in claim 4,wherein the vehicle seat is provided with a switch circuit selecting thedetection signal of any one of the head portion detecting antennaelectrode and the finger detecting antenna electrode.
 6. The vehicleseat as claimed in claim 2, wherein the finger detecting antennaelectrode is invalidated at a time when the head rest front portionmoves in the full-open position direction, and the head portiondetecting antenna electrode is invalidated at a time when the head restfront portion moves in the full-close position direction.
 7. The vehicleseat as claimed in claim 1, wherein a threshold value of the detectionsignal from the detection sensor at a time when the head rest frontportion moves in the full-open position direction is different from athreshold value of the detection signal from the detection sensor at atime when the head rest front portion moves in the full-close positiondirection.
 8. The vehicle seat as claimed in claim 1, wherein the drivemeans stops the movement of the head rest front portion in thefull-close position direction or moves the head rest front portion in anopposite direction in the case where the finger is detected between thehead rest front portion and the head rest rear portion.